#include <bits/stdc++.h>
#include <cmath>
using namespace std;

class Solution {
public:
    int search(vector<int>& nums, int target) {
        int left = 0; int right = nums.size()-1;
        while(left <= right){
            int mid = (left+right)>>1;
            if(nums[mid]==target) return mid;
            else if(nums[mid]<target) left = mid + 1;
            else if(nums[mid]>target) right = mid - 1;
        }
        return -1;
    }
};